Several inventions have been disclosed to date which employ formulated mathematical relationships to compare, test and measure signals on digital circuits with regard to binary signal changes. Some methods test the continuity of a source or signal bus as well as its short circuit occurence with a neighbouring signal bus or node have been observed. No method to date has been proposed which could compare and test static and dynamic signal levels on a test circuit, particularly when the potential level and frequency of such signals are different at different test nodes and the magnitude of signal levels are affected by the influence of environmental conditions. With the advent of sophisticated printed circuit board manufacturing, involving digital, as well as linear discrete and integrated components, the electronic manufacturing industry has been searching for an automated system that could perform desirable tests on linear circuits under the bounds of a pre-assigned tolerance level. This invention describes such methods of testing and opens a new era in the analog circuit test and troubleshooting.